Loans And Allowance For Credit Losses (Summary Of Past Due Loans (Accruing And Nonaccruing)) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 1	$ 3	$ 3	$ 8
Financing Receivable, Recorded Investment, Current		48,638		48,638		$ 46,539
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		109		109		89
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		88		88		86
Financing Receivable, Recorded Investment, Past Due		197		197		175
Loans and Leases Receivable, Gross		48,835		48,835		46,714
Accruing loans 90+ days past due		6		6		10
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	125		125		145
Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		0		0		1
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1	2	5
Financing Receivable, Recorded Investment, Nonaccrual Status		97		97		82
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross		25,287		25,287		24,162
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1	3	6
Financing Receivable, Recorded Investment, Nonaccrual Status		147		147		152
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross		11,816		11,816
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross		11,732		11,732		11,427
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		57		57		56
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		1		1		2
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0	1	1
Financing Receivable, Recorded Investment, Nonaccrual Status		49		49		67
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		0		0		1
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2	0	2
Financing Receivable, Recorded Investment, Nonaccrual Status		29		29		38
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2	0	2
Loans and Leases Receivable, Gross						11,125
Financing Receivable, Recorded Investment, Nonaccrual Status		29		29		38
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		12		12		13
One Through Four Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		44		44		42
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		1		1		0
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		11,679		11,679		11,378
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		23		23		23
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		30		30		26
Financing Receivable, Recorded Investment, Past Due		53		53		49
Loans and Leases Receivable, Gross		11,732		11,732		11,427
Accruing loans 90+ days past due		1		1		2
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	20		20		23
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						179
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						0
Financing Receivable, Recorded Investment, Past Due		1		1		1
Loans and Leases Receivable, Gross		165		165		180
Accruing loans 90+ days past due						0
Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		164		164
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		1		1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0		0
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0		0		0
Revolving Credit Facility [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						487
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						2
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						2
Financing Receivable, Recorded Investment, Past Due		4		4		4
Loans and Leases Receivable, Gross		494		494		491
Accruing loans 90+ days past due						2
Revolving Credit Facility [Member] | Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		490		490
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		3		3
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		1		1
Accruing loans 90+ days past due		1		1
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0		0		0
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						642
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						0
Financing Receivable, Recorded Investment, Past Due		0		0		1
Loans and Leases Receivable, Gross		637		637		643
Accruing loans 90+ days past due						0
Construction And Other Consumer Real Estate [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		637		637
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		0		0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0		0
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	1		1		0
One Through Four Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						7,143
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						15
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						18
Financing Receivable, Recorded Investment, Past Due		39		39		33
Loans and Leases Receivable, Gross		7,506		7,506		7,176
Accruing loans 90+ days past due						0
One Through Four Family Residential [Member] | One Through Four Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		7,467		7,467
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		13		13
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		26		26
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	13		13		19
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						2,927
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						4
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						6
Financing Receivable, Recorded Investment, Past Due		9		9		10
Loans and Leases Receivable, Gross		2,930		2,930		2,937
Accruing loans 90+ days past due						0
Home Equity Line of Credit [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		2,921		2,921
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		6		6
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		3		3
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	6		6		4
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		11,802		11,802		11,109
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		8		8		5
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		6		6		11
Financing Receivable, Recorded Investment, Past Due		14		14		16
Loans and Leases Receivable, Gross		11,816		11,816		11,125
Accruing loans 90+ days past due		0		0		1
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	23		23		26
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						8,924
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						4
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						11
Financing Receivable, Recorded Investment, Past Due		13		13		15
Loans and Leases Receivable, Gross		9,469		9,469		8,939
Accruing loans 90+ days past due						1
Term [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		9,456		9,456
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		7		7
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		6		6
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	23		23		26
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						2,185
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						0
Financing Receivable, Recorded Investment, Past Due		1		1		1
Loans and Leases Receivable, Gross		2,347		2,347		2,186
Accruing loans 90+ days past due						0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		2,346		2,346
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		1		1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0		0
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0		0		0
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		25,157		25,157		24,052
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		78		78		61
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		52		52		49
Financing Receivable, Recorded Investment, Past Due		130		130		110
Loans and Leases Receivable, Gross		25,287		25,287		24,162
Accruing loans 90+ days past due		5		5		7
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	82		82		96
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						1,661
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						0
Financing Receivable, Recorded Investment, Past Due		0		0		0
Loans and Leases Receivable, Gross		2,185		2,185		1,661
Accruing loans 90+ days past due						0
Municipal [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		2,185		2,185
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		0		0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0		0
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0		0		1
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						7,621
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						23
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						17
Financing Receivable, Recorded Investment, Past Due		49		49		40
Loans and Leases Receivable, Gross		7,924		7,924		7,661
Accruing loans 90+ days past due						3
Owner Occupied [Member] | Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		7,875		7,875
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		33		33
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		16		16
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	29		29		48
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						325
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						1
Financing Receivable, Recorded Investment, Past Due		1		1		2
Loans and Leases Receivable, Gross		332		332		327
Accruing loans 90+ days past due						0
Finance Leases Portfolio Segment [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		331		331
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		1		1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0		0
Accruing loans 90+ days past due		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0		0		1
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current						14,445
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due						37
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due						31
Financing Receivable, Recorded Investment, Past Due		80		80		68
Loans and Leases Receivable, Gross		14,846		14,846		14,513
Accruing loans 90+ days past due						4
Commercial And Industrial [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		14,766		14,766
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		44		44
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		36		36
Accruing loans 90+ days past due		5		5
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	53		53		46
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Current		141		141		89
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		0		0		0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0		0		4
Financing Receivable, Recorded Investment, Past Due		0		0		4
Loans and Leases Receivable, Gross		141		141		93
Accruing loans 90+ days past due		0		0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0		0		$ 2
Accruing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2	0	2
Accruing [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0	0	0
Accruing [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0	0	0
Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0	0	0
Accruing [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2	0	2
Accruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2	0	2
Nonaccruing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1	3	6
Nonaccruing [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1	2	5
Nonaccruing [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1	3	6
Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0	1	1
Nonaccruing [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0	0	0
Nonaccruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 0	$ 0	$ 0	$ 0

[1] ¹ Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected.